The Interaction of DOF Transcription Factors with Nucleosomes Depends on the Positioning of the Binding Site and Is Facilitated by Maize HMGB5

• Published in: Biochemistry (Easton) Vol. 42; no. 7; pp. 2149 - 2157
• Main Authors: Cavalar, Markus, Möller, Claudia, Offermann, Sascha, Krohn, Nicholas M, Grasser, Klaus D, Peterhänsel, Christoph
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25-02-2003
• Subjects: Binding Sites; DNA, Plant - chemistry; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; DOF1 protein; DOF2 protein; Electrophoretic Mobility Shift Assay - methods; HMGB Proteins - chemistry; HMGB Proteins - metabolism; HMGB5 protein; Nucleosomes - chemistry; Nucleosomes - metabolism; Plant Proteins - chemistry; Plant Proteins - metabolism; Protein Binding; Structure-Activity Relationship; Transcription Factors - chemistry; Transcription Factors - metabolism; Zea mays; Zea mays - chemistry
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi026761r

The expression of genes involved in C4 photosynthesis in maize is under tight tissue-specific and light-dependent control. There is strong evidence that this control is at least in part brought about by DOF transcription factors binding to the respective promoters. We analyzed the interaction of DOF1 and DOF2 proteins with a functional and a cryptic endogenous binding site derived from the maize phosphoenolpyruvate carboxylase promoter (−300 bp region) in the nucleosomal context. Various DNA fragments comprising this promoter region were reconstituted into mononucleosomes from purified components, resulting in different positions of the DOF binding sites on the nucleosome surface. Binding of recombinant transcription factors to the different types of nucleosomes was examined using electrophoretic mobility shift assays. Changing the translational position of the binding site on the nucleosome surface strongly affected the efficiency of the interaction with the DOF factors. Deletion of individual recognition motifs revealed a positive impact of DOF protein binding to the main binding site on interactions with the cryptic binding site. The addition of the chromosomal high-mobility group (HMG) protein HMGB5 to the binding reaction mixture facilitated nucleosome binding of the transcription factor independent from the position of the recognition sites. The relevance of the data for the activation of the promoter in vivo is discussed.